Rudder. It is amazing how much even a tiny puff of wind can move the nose off line.
If you are on "short short", just clearing the fence, your momentum will carry you onto the runway even if you are almost sideways. (But this is not good for the landing gear).
Most important here is to round out correctly at the proper airspeed (the earlier you get your approach speed right the better).
It is not unusual at all for the nose to move offline, keep flying the plane all the way down using rudder corrections to hold the nose to the line.
Only if your plane drifts towards one side or the other do we need ailerons, and this is how we do a crosswind landing: aileron holds drift, rudder holds line.
A light GA aircraft will usually pivot faster than it will drift.
The physics is that the torque turning it requires less force than to move the whole thing sideways.
But air is rarely completely calm, so be ready to use your rudder and ailerons and continue using them until the wheels stop.